\begin{tikzpicture}
	\tkzDefPoints{0/0/A, 1.4/0/B, 5.0/0/D, 3.2/0/C}
	\tkzDrawSegments[xianduan={below=0pt}](A,B  B,C  C,D)
	\tkzLabelPoints[above=0.3em](A,B,C,D)
\end{tikzpicture}

